ALMA spies 3 planets around a young star

ALMA image of a disk of material surrounding the young star HD 163296. This dusty disk have been known since 2016 to have gaps in it, presumably from newly forming planets. Now astronomers see disturbances in the disk, indicating where 3 new planets are moving within the disk. Image via ALMA (ESO/NAOJ/NRAO); A. Isella; B. Saxton (NRAO/AUI/NSF).

Two independent teams of astronomers said today (June 13, 2018) that they’ve uncovered convincing evidence for three young planets orbiting within a protoplanetary disk – or planet-forming disk – around an infant star. The star is called HD 163296. It’s 330 light-years from Earth in the direction of the constellation Sagittarius. And it’s young – really young in astronomical terms – only about 4 million years old. That’s in contrast to our sun, with 4+ billion years under its belt. These astronomers used the ALMA telescope in Chile and a new planet-finding technique. What they’ve seen are three discrete disturbances in the young star’s gas-filled disk. They said this is:

Evidence - Planets - Orbit

… the strongest evidence yet that newly formed planets are in orbit there.

ALMA stands for Atacama Large Millimeter/submillimeter Array, and this telescope has been used extensively to study protoplanetary disks since it went online officially in March, 2013. The disks around very young stars like HD 163296 are filled with gas and dust. Stars themselves – and their planets – are born out of this material. So studying the disks is like the studying the birth throes of our own Earth and sun.

Teams - Astronomers - ALMA - Conjunction - Planet-hunting

The two teams of astronomers both used ALMA in conjunction with a new planet-hunting technique that identifies unusual patterns in the flow of gas within a protoplanetary disk.

The astronomers reported their results in two separate journal articles, both in the peer-reviewed Astrophysical Journal Letters. The full references are listed at the bottom of...